Fiore is the secondary antagonist of Sailor Moon R: The Movie
Fiore was a lonely alien who took great strength when he befriended a young Mamoru Chiba just after the boy lost his parents in a car crash. But as Fiore cannot survive long on Earth's atmosphere, he left with the promise to give Mamory a flower in return for the rose the boy gave him. But Fiore ended up finding the deadly Xenian Flower, which poisoned his mind to bring her to Earth while eliminating anyone who gets in the way. While after being briefly transformed by the Xenian Flower's power, Fiore was defeated before he made a suicide attempt to stop Usagi from using the Legendary Silver Crystal's power to redirect the meteor. But once Fiore was shown Usagi's memory that she was the one who gave Mamoru the rose around the time of her little brother's birth, he allows the Xenian Flower to be destroyed.
As the Legendary Silver Crystal's use killed Usagi, Fiore fulfills his promise to Mamoru by giving him a flower containing his life to revive Usagi with its nectar. Fiore, reverted to a child as consequence, goes away by bubble after this is done.